Syria's hardline regime was grappling to contain new flare-ups after an uprising that has sharply eroded its repressive rule and has so far led to the deaths of at least 55 protesters.

There were fresh clashes in the port city of Latakia, where two people were reported to have been shot dead, as well as in the southern towns of Tafa and Deraa. They came as burials took place across the country amid international condemnation at the uncompromising force shown by the Ba'athist government that has ruled Syria for more than 40 years.

Despite the show of strength, President Bashar al-Assad has been unable to free himself from the most sustained threat to his 11-year rule, which has seen protesters attack posters of him and statues of his father, Hafez al-Assad, who ruled for 30 years. Such acts have been almost without precedent throughout four decades of totalitarian rule.

Assad had tried to stay ahead of the revolts sweeping the Arab world as they rumbled towards Syria, considered less likely to be affected than its neighbours. He had offered a string of concessions, such as heating fuel subsidies, access to previously banned social media and a three-month cut in military service.

However, his regime now appears to be facing a momentum that not even the Arab world's most feared police state could prepare for. There were reports of between 70 and 260 political prisoners being released, in what was being seen as the latest concession.

The concessions offered so far have shown no sign of containing the restive streets, which are feeding off the success of revolutions in Tunisia and Egypt as well as still simmering uprisings in Libya and Bahrain.

"These are unprecedented events in Syria," said Rime Allaf, a Syrian analyst at the Chatham House thinktank in London, "especially as they came in the wake of government promises of reform on Thursday night."

International criticism has been strident. The United Nations secretary-general, Ban Ki-moon, urged Assad to show "maximum restraint", while the US said it was deeply concerned by "the Syrian government's attempts to repress and intimidate demonstrators".

While anger grows, many Syrians remain unwilling to declare their loyalties, say analysts in Damascus. "There is not yet the critical mass needed," said one activist, who asked not to be named. Counter-demonstrations have been staged by loyalist groups and Syria's state media is not covering the protests in detail. Official media continue to blame unrest and shootings on armed gangs.

Some observers said Assad is trapped. "The regime is stuck. The less they offer, the more protests there will be; the more they offer, the faster the regime changes its dictatorial nature, and this would be the start of the end," said Bilal Saab, a Middle East analyst at the University of Maryland in the US.

Meanwhile, clashes continued on the other side of the Arabian peninsula, with Yemen's president, Ali Abdullah Saleh, on the brink of negotiating a deal for his departure, according to the country's foreign minister, Abubakr al-Qirbi.

Saleh, in power for 32 years, has been confronted by two months of youth-led street protests demanding his resignation as well as a string of defections by top military and tribal leaders. Demonstrations continuedon Saturday, but without the violence of nine days ago, which saw 53 protesters shot dead by government snipers perched on rooftops in a neighbourhood of the capital, Sana'a.

"I hope [the resignation] will be today," said al-Qirbi, who is serving as caretaker foreign minister, adding that the timeframe for a peaceful transfer of power by Saleh was "up for negotiation".

The sticking point seems to concern the fate of his family – his sons and nephews occupy powerful positions in the military – as well as the exact timing of his departure. An offer by Saleh to leave by the end of the year was snubbed by the opposition which has demanded his immediate resignation.

Sana'a remains a tense and divided capital. Rival pro- and anti-government demonstrators swept through the city as Saleh told supporters he would conditionally step aside and hand the nation to "safe hands" to avert further bloodshed after weeks of protests.

The sticking point of any discussions "is the subject of his departure", said Sakhr Wajih, an independent member of the Syrian parliament and former member of the committee for national dialogue. "It still seems, though, that the president is unwilling to seriously deal with the demands of the protesters themselves and persists in trying to draw the official opposition into a cynical deal." In Bahrain, another demonstrator reportedly died on Friday night after suffocating from the effects of tear gas. He was among a gathering in a Shia village that had been dispersed by government troops. The death takes to 21 the number of people killed in a two-month uprising that has deeply unsettled the Gulf states and led to a serious standoff between two of the region's greatest foes, Saudi Arabia and Iran.